#define _CRT_SECURE_NO_WARNINGS 1

class Solution {
    int dx[4] = { 0,0,1,-1 };
    int dy[4] = { 1,-1,0,0 };
public:
    vector<vector<int>> updateMatrix(vector<vector<int>>& mat) {
        int m = mat.size(), n = mat[0].size();
        vector<vector<int>> dist(m, vector<int>(n, -1));
        queue<pair<int, int>> q;
        for (int i = 0; i < m; i++)
        {
            for (int j = 0; j < n; j++)
            {
                if (mat[i][j] == 0)
                {
                    q.push({ i,j });
                    dist[i][j] = 0;
                }
            }
        }

        while (q.size())
        {
            auto [a, b] = q.front();
            q.pop();

            for (int i = 0; i < 4; i++)
            {
                int x = a + dx[i], y = b + dy[i];
                if (x >= 0 && x < m && y >= 0 && y < n && dist[x][y] == -1)
                {
                    dist[x][y] = dist[a][b] + 1;
                    q.push({ x,y });
                }
            }
        }
        return dist;
    }
};


class Solution {
    int dx[4] = { 0,0,1,-1 };
    int dy[4] = { 1,-1,0,0 };
    bool vis[501][501];
    int m, n;
public:
    int numEnclaves(vector<vector<int>>& grid) {
        m = grid.size(), n = grid[0].size();
        for (int i = 0; i < m; i++)
        {
            if (grid[i][0] == 1)bfs(grid, i, 0);
            if (grid[i][n - 1] == 1)bfs(grid, i, n - 1);
        }

        for (int j = 0; j < n; j++)
        {
            if (grid[0][j] == 1)bfs(grid, 0, j);
            if (grid[m - 1][j] == 1)bfs(grid, m - 1, j);
        }

        int ret = 0;
        for (int i = 0; i < m; i++)
        {
            for (int j = 0; j < n; j++)
            {
                if (grid[i][j] == 1 && !vis[i][j])
                {
                    ret++;
                }
            }
        }
        return ret;


    }


    void bfs(vector<vector<int>>& grid, int x, int y)
    {
        queue<pair<int, int>> q;
        q.push({ x,y });
        vis[x][y] = true;
        while (q.size())
        {
            auto [a, b] = q.front();
            q.pop();
            for (int i = 0; i < 4; i++)
            {
                int x = a + dx[i], y = b + dy[i];
                if (x >= 0 && x < m && y >= 0 && y < n && grid[x][y] == 1 && !vis[x][y])
                {
                    q.push({ x,y });
                    vis[x][y] = true;
                }
            }
        }
    }

};



class Solution {
    int dx[4] = { 0, 0, 1, -1 };
    int dy[4] = { 1, -1, 0, 0 };

public:
    int maxDistance(vector<vector<int>>& grid) {
        int m = grid.size(), n = grid[0].size();
        vector<vector<int>> dist(m, vector<int>(n, -1));
        queue<pair<int, int>> q;
        for (int i = 0; i < m; i++)
            for (int j = 0; j < n; j++)
                if (grid[i][j] == 1) {
                    dist[i][j] = 0;
                    q.push({ i, j });
                }

        int ret = -1;
        while (q.size()) {
            auto [a, b] = q.front();
            q.pop();
            for (int i = 0; i < 4; i++) {
                int x = a + dx[i], y = b + dy[i];
                if (x >= 0 && x < m && y >= 0 && y < n && dist[x][y] == -1) {
                    dist[x][y] = dist[a][b] + 1;
                    q.push({ x, y });
                    ret = max(ret, dist[x][y]);
                }
            }
        }
        return ret;
    }
};


class Solution {
    int dx[4] = { 0, 0, 1, -1 };
    int dy[4] = { 1, -1, 0, 0 };

public:
    vector<vector<int>> highestPeak(vector<vector<int>>& mat) {
        int m = mat.size(), n = mat[0].size();
        vector<vector<int>> dist(m, vector<int>(n, -1));
        queue<pair<int, int>> q;
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if (mat[i][j] == 0) {
                    q.push({ i, j });
                    dist[i][j] = 0;
                }
            }
        }

        while (q.size()) {
            auto [a, b] = q.front();
            q.pop();

            for (int i = 0; i < 4; i++) {
                int x = a + dx[i], y = b + dy[i];
                if (x >= 0 && x < m && y >= 0 && y < n && dist[x][y] == -1) {
                    dist[x][y] = dist[a][b] + 1;
                    q.push({ x, y });
                }
            }
        }
        return dist;
    }
};